Filtered feedthrough assembly and associated method

ABSTRACT

A system and method for sealing a capacitor bottom in a filtered feedthrough. The feedthrough comprises a ferrule, a capacitor, at least one terminal pin and a support structure. The support structure includes at least one projection that extends into an aperture of the capacitor. The projection includes an opening through which the at least one terminal pin extends such that, in an assembled state, the terminal pin extends through the opening of the projection and the aperture of the capacitor.

This application is a continuation of U.S. patent application Ser. No.12/368,847, filed Feb. 10, 2009 (pending), which is incorporated hereinby reference.

FIELD

The present disclosure relates to electrical feedthroughs forimplantable medical devices and, more particularly, a capacitor assemblyfor a filtered feedthrough.

INTRODUCTION

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent the work is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Electrical feedthroughs serve the purpose of providing an electricalcircuit path extending from the interior of a hermetically sealedcontainer to an external point outside the container. A conductive pathis provided through the feedthrough by a conductor pin which iselectrically insulated from the container. Many feedthroughs are knownin the art that provide the electrical path and seal the electricalcontainer from its ambient environment. Such feedthroughs typicallyinclude a ferrule, the conductor pin or lead and a hermetic ceramic sealwhich supports the pin within the ferrule. Such feedthroughs aretypically used in electrical medical devices such as implantable pulsegenerators (IPGs). It is known that such electrical devices can, undersome circumstances, be susceptible to electromagnetic interference(EMI). At certain frequencies for example, EMI can inhibit pacing in anIPG. This problem has been addressed by incorporating a capacitorstructure within the feedthrough ferrule, thus shunting any EMI at theentrance to the IPG for high frequencies. This has been accomplishedwith the aforementioned capacitor device by combining it with thefeedthrough and incorporating it directly into the feedthrough ferrule.Typically, the capacitor electrically contacts the pin lead and theferrule.

Many different insulator structures and related mounting methods areknown in the art for use in medical devices wherein the insulatorstructure also provides a hermetic seal to prevent entry of body fluidsinto the housing of the medical device. The feedthrough terminal pins,however, are connected to one or more lead wires which effectively actas an antenna and thus tend to collect stray or electromagneticinterference (EMI) signals for transmission to the interior of themedical device. In some prior art devices, ceramic chip capacitors areadded to the internal electronics to filter and thus control the effectsof such interference signals. This internal, so-called “on-board”filtering technique has potentially serious disadvantages due tointrinsic parasitic resonances of the chip capacitors and EMI radiationentering the interior of the device housing.

In another approach, a filter capacitor is combined directly with aterminal pin assembly to decouple interference signals to the housing ofthe medical device. In a typical construction, a coaxial feedthroughfilter capacitor is connected to a feedthrough assembly to suppress anddecouple undesired interference or noise transmission along a terminalpin.

So-called discoidal capacitors having two sets of electrode platesembedded in spaced relation within an insulative substrate or basetypically form a ceramic monolith in such capacitors. One set of theelectrode plates is electrically connected at an inner diameter surfaceof the discoidal structure to the conductive terminal pin utilized topass the desired electrical signal or signals. The other or second setof electrode plates is coupled at an outer diameter surface of thediscoidal capacitor to a cylindrical ferrule of conductive material,wherein the ferrule is electrically connected in turn to the conductivehousing or case of the electronic instrument.

In operation, the discoidal capacitor permits passage of relatively lowfrequency electrical signals along the terminal pin, while shunting andshielding undesired interference signals of typically high frequency tothe conductive housing. Feedthrough capacitors of this general type arecommonly employed in implantable pacemakers, defibrillators and thelike, wherein a device housing is constructed from a conductivebiocompatible metal such as titanium and is electrically coupled to thefeedthrough filter capacitor. The filter capacitor and terminal pinassembly prevent interference signals from entering the interior of thedevice housing, where such interference signals might otherwiseadversely affect a desired function such as pacing or defibrillating.

In the past, feedthrough filter capacitors for heart pacemakers and thelike have typically been constructed by preassembly of the discoidalcapacitor with a terminal pin subassembly which includes the conductiveterminal pin and ferrule. More specifically, the terminal pinsubassembly is prefabricated to include one or more conductive terminalpins supported within the conductive ferrule by means of a hermeticallysealed insulator ring or bead. See, for example, the terminal pinsubassemblies disclosed in U.S. Pat. Nos. 3,920,888, 4,152,540;4,421,947; and 4,424,551. The terminal pin subassembly thus defines asmall annular space or gap disposed radially between the inner terminalpin and the outer ferrule. A small discoidal capacitor of appropriatesize and shape is then installed into this annular space or gap, inconductive relation with the terminal pin and ferrule, e.g., by means ofsoldering or conductive adhesive. The thus-constructed feedthroughcapacitor assembly is then mounted within an opening in the pacemakerhousing, with the conductive ferrule in electrical and hermeticallysealed relation in respect of the housing, shield or container of themedical device.

Although feedthrough filter capacitor assemblies of the type describedabove have performed in a generally satisfactory manner, the manufactureand installation of such filter capacitor assemblies has been relativelycostly and difficult. One common method for forming a feedthrough filtercapacitor assembly is to physically couple the capacitor to theinsulating structure of the feedthrough by thermal curing of one or morenon-conductive epoxy preforms. The installation of such filter capacitorassemblies poses certain problems related to the curing of the epoxypreforms. For example, the epoxy preforms may wick into the annularcavities provided between the capacitor and the terminal pins duringcuring and thus occupy space that should be filled by a conductivematerial (e.g., epoxy, solder). This results in a degraded electricalconnection between the terminal pins and the capacitors. Additionally,the non-conductive epoxy preforms may seep into the insulating structureand cover cracks that have formed through the braze joint. This mayprevent gas from being detected during leak testing and, therefore, maycreate the impression that a satisfactory hermetic seal has been formedwhen, in fact, one has not. The use of non-conductive epoxy has beenconsidered mandatory not only because of the physical coupling of thecapacitor to the insulating structure, but also because thenon-conductive epoxy, when cured, prevents the seeping of conductivematerial, which is used to electrically couple the capacitor to the pinand ferrule, into the insulating structure of the feedthrough.

The present teachings provide a feedthrough filter capacitor assembly ofthe type used, for example, in implantable medical devices such as heartpacemakers and the like, wherein the filter capacitor is designed forrelatively simplified and economical, yet highly reliable, installation.Further, the present teachings provide a filtered feedthrough assemblyutilizing an improved capacitor attachment technique that eliminates theneed for non-conductive epoxy and prevents the undesired travel ofconductive material, such as epoxy or solder.

SUMMARY

In various exemplary embodiments, the present disclosure relates to afiltered feedthrough assembly comprising a ferrule, a capacitor, atleast one terminal pin and a support structure. The capacitor comprisesa top portion, a bottom portion, and an inner diameter portion. Theinner diameter portion of the capacitor defines at least one apertureextending from the top portion to the bottom portion. The at least oneterminal pin extends through the at least one aperture. The supportstructure is configured to be received within the ferrule, and comprisesat least one projection extending from a first side. The at least oneprojection comprises an inner circumference defining an openingextending through the support structure to a second side opposing thefirst side. The at least one projection extends into the at least oneaperture of the capacitor and the at least one terminal pin extendsthrough the opening.

In various exemplary embodiments, the present disclosure relates to amethod of assembling a filtered feedthrough assembly comprisinginserting at least one terminal pin, a support structure and a capacitorwithin a ferrule. The support structure comprises at least oneprojection extending from a first side, the at least one projectioncomprising an inner circumference defining an opening extending throughthe support structure to a second side opposing the first side. Thecapacitor comprises a top portion, a bottom portion, and an innerdiameter portion. The inner diameter portion defines at least oneaperture extending from the top portion to the bottom portion. The atleast one projection extends into the at least one aperture of thecapacitor. The at least one terminal pin extends through the opening andthrough the at least one aperture.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIGS. 1 and 2 are isometric and cross-sectional views, respectively, ofa known unipolar (single pin) feedthrough assembly prior to attachmentof a discrete discoidal capacitor;

FIGS. 3-5 illustrate a prior art method of attaching a discretediscoidal capacitor to the feedthrough assembly shown in FIGS. 1 and 2;

FIG. 6 is a cross-sectional view of a unipolar (single pin) filteredfeedthrough assembly according to various exemplary embodiments of thepresent disclosure prior to attachment of a discrete discoidalcapacitor;

FIG. 7 is a cross-sectional view of a unipolar (single pin) filteredfeedthrough assembly with an attached discrete discoidal capacitoraccording to various exemplary embodiments of the present disclosure;

FIG. 8A is a perspective side view of a support structure utilized in aunipolar (single pin) filtered feedthrough assembly according to variousembodiments of the present disclosure;

FIG. 8B is a cross-sectional view of the support structure of FIG. 8Ataken along line B-B;

FIG. 9A is a perspective side view of a support structure utilized in amultipolar (multiple pin) filtered feedthrough assembly according tovarious embodiments of the present disclosure;

FIG. 9B is a perspective top view of the support structure of FIG. 9A;

FIG. 9C is a cross-sectional view of the support structure of FIGS. 9Aand 9B taken along line C-C;

FIG. 10 is an exploded view of a multipolar (multiple pin) filteredfeedthrough assembly illustrating the attachment of a monolithicdiscoidal capacitor in accordance with various exemplary embodiments ofthe present disclosure;

FIG. 11 is a perspective view of a partially disassembled implantablemedical device; and

FIG. 12 is an isometric cutaway view of an implantable medical deviceincorporating the multipolar (multiple pin) filtered feedthroughassembly of FIG. 10.

DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the disclosure, its application, or uses. For purposesof clarity, the same reference numbers will be used in the drawings toidentify similar elements. As used herein, the phrase at least one of A,B, and C should be construed to mean a logical (A or B or C), using anon-exclusive logical or. It should be understood that steps within amethod may be executed in different order without altering theprinciples of the present disclosure.

FIGS. 1 and 2 are isometric and cross-sectional views, respectively, ofa known unipolar (single pin) feedthrough assembly 100 having a terminalpin 102 extending therethrough. Assembly 100 comprises a generallycylindrical ferrule 104 having a cavity through which pin 102 passes.Ferrule 104 is made of an electrically conductive material (e.g.,titanium alloy) and is configured to be fixedly coupled (e.g., welded)to the container of a medical device as described below in conjunctionwith FIG. 11-12. An insulating structure 106 is disposed within ferrule104 to secure pin 102 relative to ferrule 104 and to electricallyisolate pin 102 from ferrule 104. Insulating structure 106 comprises asupporting structure 108 and a joint-insulator sub-assembly 110, both ofwhich are disposed around terminal pin 102. As will be more fullydescribed below, joint-insulator sub-assembly 110 acts as an insulativeseal and may take the form of, for example, a braze joint. Supportingstructure 108 is made of a non-conductive material (e.g., polyimide) andrests on an inner ledge 112 provided within ferrule 104. As will be seenin FIG. 3, a discrete discoidal capacitor 150 may be threaded overterminal pin 102 and fixedly coupled to supporting structure 108 toattach the capacitor to feedthrough assembly 100.

As can be seen in FIG. 2, braze joint 110 comprises three maincomponents: an insulator ring 114 (e.g., made from a ceramic material)that insulates pin 102 from ferrule 104, a pin-insulator braze 116(e.g., made from gold) that couples insulating ring 114 to pin 102, andan insulator-ferrule braze 118 (e.g., made from gold) that couplesinsulating ring 114 to ferrule 104. Braze joint 110 is exposed along theunderside of ferrule 104. When ferrule 104 is fixedly coupled to thecontainer of the medical device, the lower portion of ferrule 104, andthus the lower portion of braze joint 110, may be exposed to bodyfluids. For this reason, it is important that braze joint 110 forms ahermetic seal between ferrule 104 and terminal pin 102. Braze joint 110may be leak tested. To permit this test to be performed, an aperture 120(FIG. 1) is provided through ferrule 104 to the inner annular cavityformed by the outer surface of braze joint 110, the lower surface ofsupporting structure 108, and the inner surface of ferrule 104. A gas isdelivered through aperture 120 into the inner annular cavity, andaperture 120 is plugged. Preferably, a gas of low molecular weight(e.g., helium or hydrogen) is chosen so that it may easily penetratesmall cracks in braze joint 110. Feedthrough 100 is then monitored forthe presence of the gas proximate braze joint 110 by way of, forexample, a mass spectrometer. If no gas is detected, it is concludedthat braze joint 110 has formed a satisfactory seal.

Terminal pin 102 provides a conductive path from the interior of amedical device (not shown) to one or more lead wires exterior to themedical device. As described previously, these lead wires are known toact as antennae that collect stray electromagnetic interference (EMI)signals, which may interfere with the proper operation of the device. Tosuppress and/or transfer such EMI signals to the container of themedical device, a discrete discoidal capacitor may be attached tofeedthrough assembly 100. In particular, the capacitor may be disposedaround and electrically coupled to terminal pin 102 and fixedly coupledto supporting structure 108. FIGS. 3-5 illustrate a known manner ofattaching a discrete discoidal capacitor 150 to feedthrough assembly 100shown in FIGS. 1 and 2. The attachment method commences as a ring-shapedpreform 152 of non-conductive epoxy is threaded over terminal pin 102(indicated in FIG. 3 by arrow 154). Capacitor 150 is then threaded overpin 102 and positioned against preform 152 such that preform 152 issandwiched between capacitor 150 and supporting structure 108. Next,feedthrough assembly 100 is placed within a curing oven and heated to apredetermined temperature (e.g., approximately 175 degrees Celsius) tothermally cure preform 152 (indicated in FIG. 4 by arrows 156) and thusphysically couple capacitor 150 to supporting structure 108.

During curing, preform 152 melts and disperses under the weight ofcapacitor 150, which moves downward toward supporting structure 108.Preform 152 disperses along the annular space provided between thebottom surface of capacitor 150 and the upper surface of supportingstructure 108 to physically couple capacitor 150 and supportingstructure 108 as described above. In addition, preform 152 may disperseupward into the annular space provided between the inner surface ofcapacitor 150 and outer surface of terminal pin 102 (shown in FIG. 5 at158). Dispersal of preform 152 in this manner may interfere with theproper electrical coupling of capacitor 150 to terminal pin 102. Also,during curing, preform 152 may disperse downward into insulatingstructure 110 (shown in FIG. 5 at 160). This dispersal may result inpreform 152 covering any cracks that have formed through braze joint 110and, consequently, prevent the accurate leak testing of feedthroughassembly 100.

Referring now to FIGS. 6-7, a filtered feedthrough assembly 200according to various exemplary embodiments of the present disclosure isillustrated. Filtered feedthrough assembly 200 is unipolar (single pin)and has a terminal pin 202 extending therethrough. Assembly 200comprises a generally cylindrical ferrule 204 having a cavity throughwhich pin 202 passes. Ferrule 204 is made of an electrically conductivematerial (e.g., titanium alloy) and is configured to be fixedly coupled(e.g., welded) to the container of a medical device as described belowin conjunction with FIGS. 11-12. An insulating structure comprisingsupporting structure 280 and a joint-insulator sub-assembly 210 isdisposed within ferrule 204 to secure pin 202 relative to ferrule 204and to electrically isolate pin 202 from ferrule 204. Both of thesupporting structure 280 and a joint-insulator sub-assembly 210 aredisposed around terminal pin 202. The joint-insulator sub-assembly 210acts as an insulative seal and may take the form of, for example, abraze joint. As described more fully below, supporting structure 280 ismade of a non-conductive material (e.g., polyimide, polyetheretherketone(PEEK) or similar material) and rests on an inner ledge 212 providedwithin ferrule 204. As will be seen, a discrete discoidal capacitor maybe threaded over terminal pin 202 and fixedly coupled to supportingstructure 280 to attach the capacitor to feedthrough assembly 200.

Braze joint 210 comprises three main components: an insulator ring 214(e.g., made from a ceramic material) that insulates pin 202 from ferrule204, a pin-insulator braze 216 (e.g., made from gold) that couplesinsulating ring 214 to pin 202, and an insulator-ferrule braze 218(e.g., made from gold) that couples insulating ring 214 to ferrule 204.Braze joint 210 is exposed along the underside of ferrule 204. Whenferrule 204 is fixedly coupled to the container of the medical device,the lower portion of ferrule 204, and thus the lower portion of brazejoint 210, may be exposed to body fluids. For this reason, it isimportant that braze joint 210 forms a hermetic seal between ferrule 204and terminal pin 202, which may be leak tested, as described above.

Terminal pin 202 provides a conductive path from the interior of amedical device (not shown) to one or more lead wires exterior to themedical device. As described previously, these lead wires are known toact as antennae that collect stray electromagnetic interference (EMI)signals, which may interfere with the proper operation of the device. Tosuppress and/or transfer such EMI signals to the container of themedical device, a discrete discoidal capacitor 250 may be attached tofeedthrough assembly 200. In particular, the capacitor 250 may bedisposed around and electrically coupled to terminal pin 202 and fixedlycoupled to supporting structure 280, described more fully below.

The capacitor 250 includes a top portion 252, a bottom portion 254, aninner diameter portion 256 and an outer diameter portion 258. The innerdiameter portion 256 defines an aperture 255, extending from the topportion 252 to the bottom portion 254, through which the terminal pin202 extends. In the assembled filtered feedthrough assembly 200, theinner diameter portion 256 of capacitor 250 is electrically coupled tothe terminal pin 202, e.g., by means of solder or conductive epoxy 257.Similarly, the outer diameter portion 258 of capacitor 250 iselectrically coupled to the ferrule 204, e.g., by means of solder orconductive epoxy 259. The inner and outer diameters 256, 258 are eachelectrically coupled with one of the two sets of electrode plates thatare electrically isolated from one another and form the capacitor 250.

Referring now to FIGS. 6-9C, a support structure 280 according tovarious exemplary embodiments of the present disclosure is illustrated.As shown in FIGS. 6-7, support structure 280 is sized and configured tobe received within ferrule 204. In the illustrated example, supportstructure rests upon an inner ledge 212 provided within ferrule 204. Asshown in FIGS. 8A-9C, support structure 280 may be designed for use in aunipolar, i.e., single pin, feedthrough assembly as shown in FIGS. 8A-B,or a multipolar, i.e., multiple pin, feedthrough assembly as shown inFIGS. 9A-C. The design differences between a unipolar and multipolarsupport structure 280 are minor and essentially equate to including thecorrect number of openings within support structure 280 to accommodatethe number of terminal pin(s) 202 in the feedthrough.

The support structure 280 comprises at least one projection 281extending from a first side 282 of the support structure 280. The innercircumference 284 of the projection 281 defines an opening 285 thatextends through the support structure 280 from the first side 282 to asecond side 283 opposed thereto. In some exemplary embodiments, theprojection 281 includes a cylindrical base portion 286 and a chamferedportion 287. The chamfered portion 287 simplifies insertion of theprojection 281 into the aperture 255 of the capacitor 250, as describedmore fully below.

The opening 285 is sized to receive and mate with terminal pin 202. Insome exemplary embodiments, the opening 285 is sized such that theterminal pin 202 is tightly secured in the opening 285, e.g., to createa seal between terminal pin 202 and opening 285. In the exemplaryembodiment illustrated in FIGS. 9A-C, the projection 281 is comprised ofa bifurcated cylindrical base portion, which is, in its simplest form, acylindrical projection 281 that is split in two, or more, portions. Thesplit allows for elastic deformation of the projection 281 such that theouter diameter of terminal pin 202 may be greater than the innercircumference 284 of opening 285 in a non-deformed state. Upon insertionof terminal pin 202 into opening 285, the portions of the projection 281expand outwardly to accommodate the terminal pin 202, while theresiliency of the projection 281 portions provides a force upon terminalpin 202 to assist in the securing and sealing of the terminal pin 202 inopening 285. Additionally, the walls of the opening 285 may besubstantially straight, as shown in FIGS. 8A-B, or otherwise contoured,e.g., tapered to provide a conical cross-section as shown in FIGS. 9A-C,to assist in the insertion of terminal pin 202 into the opening 285.

The filtered feedthrough assembly 200 according to various exemplaryembodiments may be assembled as follows. The joint-insulatorsub-assembly 210 is disposed within ferrule 204 to secure pin 202relative to ferrule 204 and to electrically isolate pin 202 from ferrule204, as described more fully above. Support structure 280 may then beinserted within ferrule 204 such that terminal pin 202 extends throughopening 285. As described above, the opening 285 of support structure280 may be sized so as to mate with terminal pin 202 in a securefashion. A partially assembled filtered feedthrough assembly 200according to various exemplary embodiments of the present disclosure isillustrated in FIG. 6.

Capacitor 250 is then inserted at least partially within the ferrule 204such that terminal pin 202 extends through, and the projection 281 ispartially received within, aperture 255. In some exemplary embodiments,projection 281 and aperture 255 are sized such that the projection 281is tightly secured in the aperture 255, e.g., to create a seal betweenprojection 281 and aperture 255. In this manner, support structure 280may be physically coupled to capacitor 250 without the use ofnon-conductive epoxy or other compound as in the prior art, which notonly simplifies the assembly process, but also prevents the intrusion ofthe non-conductive epoxy into the joint-insulator sub-assembly 210.Furthermore, projection 281 may be sized and positioned such that theterminal pin 202 is substantially centered within aperture 255, whichwill assist in the formation of a reliable electrical connection betweencapacitor 250 and terminal pin 202.

After placement of capacitor 250 within ferrule 204, the inner diameterportion 256 of capacitor 250 is electrically coupled to the terminal pin202, e.g., by means of solder or conductive epoxy 257. Similarly, theouter diameter portion 258 of capacitor 250 is electrically coupled tothe ferrule 204, e.g., by means of solder or conductive epoxy 259.Support structure 280, and specifically the coupling of aperture 255 andprojection 281, inhibits or prevents the flow of solder or conductiveepoxy 257, 259 into the joint-insulator sub-assembly 210. A fullyassembled filtered feedthrough assembly 200 according to variousexemplary embodiments of the present disclosure is illustrated in FIG.7.

FIG. 10 illustrates the attachment of a monolithic discoidal capacitor300 to a multipolar feedthrough assembly 302 in accordance with avarious exemplary embodiments of the present invention. Filteredfeedthrough assembly 302 comprises a ferrule 306 and an insulatingstructure 304 disposed within ferrule 306. Filtered feedthrough assembly302 guides an array of terminal pins 305 through the container of amedical device to which ferrule 304 is coupled (shown in FIG. 12). Asdescribed above, terminal pin array 305 and the lead wires to whicharray 305 is coupled may act as an antenna and collect undesirable EMIsignals. Monolithic discoidal capacitor 300 may be attached tofeedthrough assembly 302 to provide EMI filtering. Capacitor 300 isprovided with a plurality of terminal pin-receiving apertures 310therethrough. Capacitor 300 is inserted over terminal pin array 305 suchthat each pin in array 305 is received by a different aperture 310 andplaced in an abutting relationship with insulating structure 304. Ifdesired, one terminal pin in array 305 may be left unfiltered as shownin FIG. 10 to serve as an RF antenna. Support structure 380 is providedbetween insulating structure 304 and capacitor 300. Capacitor 300 may becoupled to support structure 380, such as by projections 381 on supportstructure 380 being securely received within terminal pin-receivingapertures 310, similarly to that discussed above in regard to a unipolarfeedthrough assembly 200. Furthermore, a sleeve 382 may be included onsupport structure 380 to assist in the isolation of the unfiltered pin305U from capacitor 300.

FIG. 11 is an exploded view of an implantable medical device (e.g., apulse generator) 350 coupled to a connector block 351 and a lead 352 byway of an extension 354. The proximal portion of extension 354 comprisesa connector 356 configured to be received or plugged into connectorblock 351, and the distal end of extension 354 likewise comprises aconnector 358 including internal electrical contacts 360 configured toreceive the proximal end of lead 352 having electrical contacts 362thereon. The distal end of lead 352 includes distal electrodes 364,which may deliver electrical pulses to target areas in a patient's body(or sense signals generated in the patient's body, e.g., cardiacsignals).

After a capacitor 300 has been attached to feedthrough assembly 302 inthe manner described above, assembly 302 may be welded to the housing ofan implantable medical device 350 as shown in FIG. 12. Medical device350 comprises a container 352 (e.g. titanium or other biocompatiblematerial) having an aperture 354 therein through which feedthroughassembly 302 is disposed. As can be seen, each terminal pin in array 305has been trimmed and is electrically connected to circuitry 356 ofdevice 350 via a plurality of connective wires 358 (e.g., gold), whichmay be coupled to terminal pin array 305 by wire bonding, laser ribbonbonding, or the like. After installation, feedthrough assembly 302 andcapacitor 300 collectively function to permit the transmission ofrelatively low frequency electrical signals along the terminal pins inarray 305 to circuitry 356 while shunting undesired high frequency EMIsignals to container 352 of device 350.

The broad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims.

What is claimed is:
 1. A filtered feedthrough assembly, comprising: aferrule; a capacitor comprising a top portion and a bottom portion,wherein at least one aperture is defined through the capacitor from thetop portion to the bottom portion; at least one terminal pin extendingthrough the at least one aperture; and a support structure configured tobe received within the ferrule, wherein the support structure comprises:a first side; a second side opposing the first side; and at least oneprojection extending from the first side prior to insertion of the atleast one terminal pin through the support structure, wherein an openingis defined through the at least one projection and extends to the secondside of the support structure, wherein the at least one projection ofthe support structure extends into the at least one aperture of thecapacitor such that a seal is created between the at least oneprojection and the at least one aperture defined through the capacitor,wherein the seal is created between the at least one projection and theat least one aperture defined through the capacitor when and upon theinsertion of the at least on projection of the support structure intothe at least one aperture of the capacitor, and further wherein the atleast one terminal pin extends through the opening defined through theat least one projection such that the at least one terminal pin issealed in the opening defined through the at least one projection,wherein another seal is created between the at least one terminal pinand the opening defined through the at least one projection when andupon insertion of the at least one terminal in the opening definedthrough the at least one projection.
 2. The filtered feedthroughassembly of claim 1, wherein the at least one projection comprises abifurcated cylindrical base portion.
 3. The filtered feedthroughassembly of claim 1, wherein the opening tapers from the second side tothe first side such that the opening has a conical cross-section.
 4. Thefiltered feedthrough assembly of claim 1, wherein the second side of thesupport structure rests on an inner ledge of the ferrule.
 5. Thefiltered feedthrough assembly of claim 1, wherein the capacitor furthercomprises an outer diameter portion and an inner diameter portiondefining the at least one aperture of the capacitor, the inner diameterportion being electrically coupled to the at least one terminal pin andthe outer diameter portion being electrically coupled to the ferrule. 6.The filtered feedthrough assembly of claim 1, wherein the at least oneprojection comprises a cylindrical base portion and a chamfered portion.7. The filtered feedthrough assembly of claim 1, wherein the supportstructure centers the at least one terminal pin within the at least oneaperture.
 8. The filtered feedthrough assembly of claim 1, wherein theat least one projection comprises two or more deformable portions. 9.The filtered feedthrough assembly of claim 8, wherein the at least oneprojection comprises a cylindrical base portion extending from the firstside of the support structure, the two or more deformable portionsextending from the cylindrical base portion.
 10. A filtered feedthroughassembly, comprising: a ferrule; a capacitor comprising a top portionand a bottom portion, wherein a plurality of apertures are definedthrough the capacitor from the top portion to the bottom portion; atleast one terminal pin extending through the at least one aperture; anda support structure configured to be received within the ferrule,wherein the support structure comprises: a first side; a second sideopposing the first side; and a plurality of projections extending fromthe first side thereof, wherein an opening is defined through each ofthe projections of the plurality of projections with the openingextending to the second side of the support structure, wherein each ofone or more projections of the plurality of projections extends into acorresponding aperture of the capacitor such that a seal is createdbetween the projection and the corresponding aperture, and furtherwherein each of one or more terminal pins of the plurality of terminalpins extends through a corresponding opening defined through aprojection of the plurality of projections such that the terminal pin issecured and sealed in the corresponding opening.
 11. The filteredfeedthrough assembly of claim 10, wherein the number of aperturesdefined through the capacitor is less than the number of projectionsextending from the first side of the support structure such that atleast one terminal pin extending through at least one opening definedthrough at least one projection of the plurality of projections is notcoupled to the capacitor.
 12. A filtered feedthrough assemblycomprising: a ferrule; a capacitor comprising a top portion and a bottomportion, wherein at least one aperture is defined through the capacitorfrom the top portion to the bottom portion; at least one terminal pinextending through the at least one aperture; and a support structureconfigured to be received within the ferrule, wherein the supportstructure comprises: a first side; a second side opposing the firstside; and at least one projection extending from the first side, whereineach projection of the at least one projection comprises two or moredeformable portions, wherein an opening is defined through the at leastone projection and extends to the second side of the support structure,wherein the at least one projection of the support structure extendsinto the at least one aperture of the capacitor, and further wherein theat least one terminal pin extends through the opening defined throughthe at least one projection, wherein a seal is created between the atleast one projection and the at least one aperture defined through thecapacitor when and upon the insertion of the at least one projection ofthe support structure into the at least one aperture of the capacitor,and further wherein another seal is created between the at least oneterminal pin and the opening defined through the at least one projectionwhen and upon insertion of the at least one terminal in the openingdefined through the at least one projection.
 13. The filteredfeedthrough assembly of claim 12, wherein the at least one projectioncomprises a cylindrical base portion extending from the first side ofthe support structure, the two or more deformable portions extendingfrom the cylindrical base portion.
 14. The filtered feedthrough assemblyof claim 12, wherein each of the two or more deformable portionsterminates in a chamfered portion.
 15. The filtered feedthrough assemblyof claim 12, wherein the at least one projection comprises a bifurcatedcylindrical base portion.
 16. The filtered feedthrough assembly of claim12, wherein the second side of the support structure rests on an innerledge of the ferrule.
 17. The filtered feedthrough assembly of claim 12,wherein the capacitor further comprises an outer diameter portion and aninner diameter portion defining the at least one aperture of thecapacitor, the inner diameter portion being electrically coupled to theat least one terminal pin and the outer diameter portion beingelectrically coupled to the ferrule.
 18. A filtered feedthrough assemblycomprising: a ferrule; a capacitor comprising a top portion and a bottomportion, wherein a plurality of apertures are defined through thecapacitor from the top portion to the bottom portion; at least oneterminal pin extending through the at least one aperture; and a supportstructure configured to be received within the ferrule, wherein thesupport structure comprises: a first side; a second side opposing thefirst side; and a plurality of projections extending from the first sidethereof, wherein the at least one projection comprises two or moredeformable portions, wherein an opening is defined through each of theprojections of the plurality of projections with the opening extendingto the second side of the support structure, wherein each of one or moreprojections of the plurality of projections extends into a correspondingaperture of the capacitor such that a seal is created between theprojection and the corresponding aperture, and further wherein each ofone or more terminal pins of the plurality of terminal pins extendsthrough a corresponding opening defined through a projection of theplurality of projections such that the terminal pin is secured andsealed in the corresponding opening.
 19. The filtered feedthroughassembly of claim 18, wherein the number of apertures defined throughthe capacitor is less than the number of projections extending from thefirst side of the support structure such that at least one terminal pinextending through at least one opening defined through at least oneprojection of the plurality of projections is not coupled to thecapacitor.
 20. A filtered feedthrough assembly, comprising: a ferrule; acapacitor comprising a top portion and a bottom portion, wherein atleast one aperture is defined through the capacitor from the top portionto the bottom portion; at least one terminal pin extending through theat least one aperture; and a support structure configured to be receivedwithin the ferrule, wherein the support structure comprises: a firstside; a second side opposing the first side; and at least one projectionextending from the first side prior to insertion of the at least oneterminal pin through the support structure, wherein the at least oneprojection is monolithic with the first side, wherein an opening isdefined through the at least one projection and extends to the secondside of the support structure, wherein the at least one projection ofthe support structure extends into the at least one aperture of thecapacitor such that a seal is created between the at least oneprojection and the at least one aperture defined through the capacitor,and further wherein the at least one terminal pin extends through theopening defined through the at least one projection such that the atleast one terminal pin is sealed in the opening defined through the atleast one projection.
 21. The filtered feedthrough assembly of claim 20,wherein a circumferential edge extends between the first side and secondside, and further wherein an area defined by a cross-sectionalcircumference of the at least one projection is less than an areadefined by the circumferential edge.
 22. A filtered feedthroughassembly, comprising: a ferrule; a capacitor comprising a top portionand a bottom portion, wherein at least one aperture is defined throughthe capacitor from the top portion to the bottom portion; at least oneterminal pin extending through the at least one aperture; and a supportstructure configured to be received within the ferrule, wherein thesupport structure comprises: a first side; a second side opposing thefirst side; and at least one projection extending from a the first sideprior to insertion of the at least one terminal pin through the supportstructure, wherein an opening is defined through the at least oneprojection and extends to the second side of the support structure,wherein the second side having the opening defined therein liessubstantially along a plane, wherein the at least one projection of thesupport structure extends into the at least one aperture of thecapacitor such that a seal is created between the at least oneprojection and the at least one aperture defined through the capacitor,and further wherein the at least one terminal pin extends through theopening defined through the at least one projection such that the atleast one terminal pin is sealed in the opening defined through the atleast one projection.
 23. The filtered feedthrough assembly of claim 22,wherein the support structure lacks any portion thereof that extendsbeyond the plane along which the second side lies in a directionopposite of the at least one projection extending from the first side.24. A filtered feedthrough assembly, comprising: a ferrule; a capacitorcomprising a top portion and a bottom portion, wherein at least oneaperture is defined through the capacitor from the top portion to thebottom portion; at least one terminal pin extending through the at leastone aperture; and a support structure configured to be received withinthe ferrule, wherein the support structure comprises: a first side; asecond side opposing the first side; and at least one projectionextending from the first side prior to insertion of the at least oneterminal pin through the support structure, wherein an opening isdefined through the at least one projection and extends to the secondside of the support structure, wherein the at least one projection ofthe support structure extends into the at least one aperture of thecapacitor such that a seal is created between the at least oneprojection and the at least one aperture defined through the capacitor,wherein the at least one terminal pin extends through the openingdefined through the at least one projection such that the at least oneterminal pin is sealed in the opening defined through the at least oneprojection, wherein the support structure comprises only the at leastone projection, and further wherein any and all projections of the atleast one projection extend in only a first direction relative to thefirst side of the support structure.